【摘要】 利用原子力显微镜和透射电镜分析了聚苯乙烯辐射接枝纳米二氧化硅粒子(SiO2-g-PS)填充聚丙烯(PP)的微观结构,并与该复合材料的拉伸和冲击强度相关联,为探讨纳米粒子的增强增韧作用机制提供了直观证据。利用原子力显微镜进行的微划痕和纳米压痕实验,通过与显微硬度和动态力学性能测试结果的比较,证实了接枝改性后的纳米粒子团聚体具有承载能力,而这些团聚体对复合材料的局部和整体力学响应不同,揭示了团聚体增强效应的内在原因,即在纳米粒子团聚体内部以及团聚体之间形成了特定的应力双逾渗结构。更多还原

【Abstract】 Polypropylene(PP) was reinforced with nano-silica pretreated by grafting polystyrene onto the particles.The microstructure of the composites was studied by using atomic force microscopy(AFM) and transmission(electron) microscopy(TEM).The observations were correlated with the tensile and impact properties of the compo-sites.In order to illuminate the role of silica agglomerates in the composites,microscratching and nanoindentation were investigated using AFM.The microhardness and dynamic mechanical properties(DMA)were examined as a(reference).It was found that the grafted silica agglomerates possess load-bearing capacity,leading to different(responses) of the composites against the microhardness and DMA measurements.The results present direct evidence for the effect of the treated nano-silica agglomerates on the mechanical behavior of polypropylene.That is,the dou-ble percolation behavior of stress volumetric spheres accounted for the significant improvement on the mechanical properties of the composites.更多还原